Dynamic Safety Evaluating Based on Project Network Schedule Xu Chengxiang Zhang Jianshe Assoc. Prof., School of Construction Engineering, Tianjin University, Tianjin 300072, China.The project constructions are usually faced with many unsafe factors that bring great harm to workers and equipment. In this paper, a dynamic safety analysis model was presented using hazard index relating to an activity and overall project in construction. The hazard index was used to describe the unsafe level of single activity, and the overall unsafe level of the construction was described by the accumulation of the hazard index for all activities being conducted simultaneously in the construction. The results then can be used to provide the construction managers with useful information. At the end, an example was analyzed with this method.project construction; dynamic safety evaluating; man machine engineering